Light mediated dual phosphine/copper catalyzed atom transfer radical addition reaction.

Abstract

The atom transfer radical addition reaction catalyzed by triphenylphosphine and copper(I) halide is described. The reaction proceeds under irradiation with 365 nm light using a light emitting diode, and performed in a regular glassware. The proposed mechanism involves the formation of quaternary phosphonium salt, which undergoes single electron reduction by the copper(I) salt via photoinduced electron transfer. The method works well for terminal alkenes and activated organic halides such as esters of bromo- and iodoacetic acid and bromoacetonitrile. gem-Difluorinated styrenes, for which atom transfer reactions are rare, also proved to be good substrates for this phosphine/copper catalyzed protocol.